Late Me 109 G & K engine settings

[mw]

Thanks Guppy35.

[Angus]

This is all quuite funny.
Well, what would life be without Barbi, eh?
Anyway, - this:

"But only 650 liters of fuel compared to 900 liters of fuel consumed by the Merlins at the same power. We speak of fuel effiency here, not 'liquid effiency' - never heard of such."

Getting out of the crossfire there?
Well. MW is injected into the engine, is necessary to boost power, and does carry a weight penalty. You can replace it with----less power. So if you want to speak of fuel economy, you should keep with power without MW and fuel consumption, - or power With MW with MW included. Dead simple.
Anyway, I have a feeling that actually the common use to the latest part of the war would have been 1.3/1.42 in most cases.
Will ask my LW lot about it. Just in case

[butch2k]

1.98 was achievable with C3 only on the DC but the overheating was coming just too fast to make it really an operational feature. The advantage was to prevent instantaneous engine destruction in case MW-50 was not delivered to the engine anymore.
Good quality C3 had the capability to run at 2.2 ata @ 8.5CR, at least it could sustain such pressures without detonating, it does not mean it could be achieved in operational condition without MW-50 as a coolant.
MW-50 was both an anti-detonant (think of B4+MW-50 required on a DB605DB @ 1.8ata) and a coolant preventing overheating (by water vaporisation taking a lot of the residual heat of fuel combustion)

[eddiek]

You guys getting dizzy yet?
Around and around and around............

Kufurst, I don't have anything against you, and I am not taking sides, but.......if YOU are gonna mention butch2k as a source to back up your claims, then turn around and say "he said it, I didn't", it kinda makes you look, well...........fishy....
Like Milo said, too, your scanned docs don't match up, but that is to be expected.  Doesn't matter if documents from that era are Allied or Axis, there pretty much seems to be discrepancies somewhere from document to document.  
FWIW, IF the DB series engines were more fuel effecient than their Allied counterparts, who cares?  It didn't affect the outcome of the war, they didn't do anything with that extra effeciency, so what's the point in arguing about it?
This has taken on an air of someone trying to play up how wonderful the Nazis were (and I don't wanna hear it.....if you fought/flew for German in WW2, you WERE fighting for them) and making excuses/alibis for why they ultimately lost the war.

 think I'm through with this thread.  Lotsa words passing back and forth, nothing being accomplished

[Angus]

Well, like I said, it will boil down to the actual combat ranges applied in WW2.
109's breaking off escort before reaching London because of fuel shortage means breaking off a mission with direct range of 100 miles for instance.....

[JG_Sunbird]

[pasoleati]

First, DB 605´s max continuous coolant outlet T is 115 deg C. Merlin´s max continuous is 105 deg C. So where is the extreme? Kurrie quoted 135 deg C, but nicely forgot to mention that it is the 5 minute emergency limit.

Second, why it is that every other major manufacturer of large aero engines obtained maximum power by having low CD/high boost combo. Makers like BMW, Junkers, Bristol, RR, Allison, Napier, Wright, P&W.

Why did turbocharged, with very high boost, 1.5 litre Formula One engines utterly and decisively beat their unsupercharged 3.5 litre opponents to pulp? Why is every form of motor racing where supercharging is allowed dominated by highly boosted supercharged engines instead of Kurfürst high CR crap? I don´t think Kurfürst needs more coffin nails. He´s doomed.

[gripen]

Pasoleati,
Eipä tuon tohtori koon kanssa ole faktoilla mitään väliä; kyse on uskonnosta.

gripen

[pasoleati]

Niinpä. Asiallinen keskustelu olisi tervetullutta, mutta jos musta on väkisin väännettävä valkoiseksi, ei siitä tule mitään.

[Kurfürst]

Originally posted by pasoleati
First, DB 605´s max continuous coolant outlet T is 115 deg C. Merlin´s max continuous is 105 deg C. So where is the extreme? Kurrie quoted 135 deg C, but nicely forgot to mention that it is the 5 minute emergency limit.

[/B]

You`d have to check a reference before making such statements, as such examples only prove most of what you say is only your guessing.

The DB 605A manual right in front of me states that 115 degrees are permissable for 10 minutues only, whereas 102 degrees is for permissable continously. Such limits are generally defined by the boiling limit and coolant reserve, and it 135 vs 115, 105 vs 102 clearly shows RR was using higher pressures.

In brief you had no idea of what you were talking about.

Second, why it is that every other major manufacturer of large aero engines obtained maximum power by having low CD/high boost combo. Makers like BMW, Junkers, Bristol, RR, Allison, Napier, Wright, P&W.

[/B]

Wrong.

Napier Sabre used 7 : 1 high CR with relatively low boost of +7, just like DB did.
The BMW 801 used 7.22 : 1 high CR with low boost, just like DB did.
Wright also progressively increased the CR, ie. earlier to later Wright engines  :

Whirlwind : 6,1 : 1
Cyclone 9R : 6.4 : 1
Cyclone 9R R-1820 : 6.7 : 1
Cyclone 14 GR 2600 : 6.9 : 1

DB was using 6.9 : 1 in it`s initial models, increasing it to 7.3 in the 605, then finally to 8.3-8.5 with the models using higher grade fuels.

The trend is clear, every later engine, except RR`s was heading towards direct fuel injection, larger volumes and higher CR, which was exactly the path pioneered and followed. All the engine manufacturers I noted successfully ended up with 2000+ HP engines, whereas Allison who followed the stupid RR struggled to get past 1600 HP, even with a monstre turbocharger.

In brief you had no idea of what you were talking about, again, and just made yourself look laughable with this tunnel vision about everything DB made was wrong. Yeah I wonder why did it become the largest engine manufacturer in Germany, and why the LW choosed it`s engines over BMW and Junkers over and over again.

Röviden szólva valószínüleg te is olyan beszükült seggfej vagy mint Gripen, aki reggeltöl estig vakon szajkózza a magáét, és semmiféle észérve sem produkál életjeleket. Persze nagyon szívesen alázlak téged is.

[pasoleati]

Well, you have a different manual. I have the Finnish edition for "DB 605 A-C" which clearly says 115 deg C is permitted at sea level and there is no time limit either on that page nor anywhere else in that manual.

[pasoleati]

And K, would you mind checking the manifold pressure of Wright Whirlwind vs. R-3350? Your example is so amusing that I don´t know whether to laugh or weep.

As for the Sabre, would you mind checking the CR and boost figs for Sabre II and Sabre V? You will note that the CR remained the same whereas the additional power was solely due to increased boost!

And Allison struggled to pass 1600 hp? G-series (with reduced CR but increased boost) produced some 2200 hp.

The same trend in the P&W R-2800. All power increases within a series (e.g. B and C) was obtained with increased boost, not by increasing CR.

Monster turbocharger? Been watching too many horror movies?

As for LW choosing DB over others, lets see what Dr. Otto Cuno of Rechlin (from January 1944 the head of German engine development in Berlin) said in an interrogation by RAE in September 1945 (tbc)

[pasoleati]

Otto Cuno: "...We therefore planned to develop jets and rockets and stopped many developments on piston engines. For the latter [emphasis added] WE CONCENTRATED ON THE JUMO 213 AND AS AN INSURANCE POLICY THE DB 603 AS WELL,...". So, do you still claim that LW somehow chose DB over and over again?

Cuno also mentions that they were obtaining 2700 hp from the Jumo 213 in July 1944 test. 2700 hp from slightly lesser volume that of the DB 605 and a volume from which the almighty DB was struggling to get over 2000 hp...

[pasoleati]

One more thing. It is obvious for anyone with brains why the DB might have had lower coolant temps: poor design. It is pretty clear that the 605 suffered from far too many piston scorching problems as proven by tech orders explaining why the 1.42 ata setting is banned.  As higher coolant temperature would naturally mean higher piston temperature, lower coolant temperature would have been just another way to patch up the sinking ship. After all, the almighty DB geniuses were the only major designers to adopt dry cylinder liners with their much poorer heat transfer properties.

[Kurfürst]

Well, you have a different manual. I have the Finnish edition for "DB 605 A-C" which clearly says 115 deg C is permitted at sea level and there is no time limit either on that page nor anywhere else in that manual.

I have the original German from automn 1942. As well a the Hungarian from 1943. It appears the Finnish isn`t accurate.

As for the Sabre, would you mind checking the CR and boost figs for Sabre II and Sabre V? You will note that the CR remained the same whereas the additional power was solely due to increased boost!

First you claimed nobody used high CR, then when proven utterly wrong in that, you change the claim? The Sabre Started out with +7 lbs boost, similiar what the Germans were using that time. Germans went the same way, increasing MAP continously, as well as CR with the higher octane fuels. So WTF you are talking about, more nonsense?


Monster turbocharger? Been watching too many horror movies?

How much Finlandia do you drink before posting? Should I say, P-47, a six ton monster? Should I point to a NACA report on supercharger technology, that points out that installing a similiar effiency turbocharger means 500 lbs extra weigth, whereas a DVL hydraulic cluthc comes with... 50 lbs extra?

Cuno also mentions that they were obtaining 2700 hp from the Jumo 213 in July 1944 test. 2700 hp from slightly lesser volume that of the DB 605 and a volume from which the almighty DB was struggling to get over 2000 hp...

Oh yes, largely by diverting less power to the supercharger, thus increasing peak low level output at the expense of altitude performance.  What`s the big deal, DB did that in 1939, when it pumped out 2700 HP from a DB 601, that`s it, an engine 200 kg lighter and smaller displacement than the Jumo. And it even flew.


oh yes, 900kg + Jumo 213 vs 740 kg DB 605, heh? I guess something for something. DB struggling to get over 2000 HP? That`s laughalbe, they introduced into combat service. As for test engines, DB had nice developments as well, the DB 603 N was producing 2900 PS and had an unmached 2000 PS+ output even at 10 000m, at the same weight as Jumos, I`d like to see an engine that did the same. Your bias against DB is far too obvious. Fact still is, Junkers engines were turned down again and again to be used in fighters. They put them into bombers, and that tells the whole story, the only one that got it was the _interim solution_ D-9s, and the Ta 152H. Even the Ta 152C received the DB 603, so did the Do 335. Junkers tried hard to knock out DB during the war, but ultimately it always failed.

So, do you still claim that LW somehow chose DB over and over again?

There`s nothing to claim here, it`s a fact that they did.